Golf club head of iron or wood type

ABSTRACT

Head ( 1 ) of a golf club of the “wood” or “iron” type, having a wall forming the striking face ( 2 ), at least one wall adjacent the wall forming the striking face ( 2 ), namely in particular the wall of the sole ( 3 ), and which also comprises an elastic leaf ( 12 ) one end ( 13 ) of which is fixed to one of the walls ( 6 ) adjacent the wall forming the striking face ( 2 ), and the free other end ( 14 ) of which presses the preload against the back face ( 11 ) of the wall of the striking face ( 2 ).

TECHNICAL FIELD

[0001] The invention relates to the field of golf. It is aimed morespecifically at a novel structure of the head of a golf club of the“wood” or “iron” type. The invention makes it possible to optimize thetrampolining effects of the striking face.

PRIOR ART

[0002] In general, golf clubs the heads of which are initially made ofsolid wood before they were made even of hollow metal or of compositeare known as “woods”.

[0003] The invention protects the type of clubs known as woods theinterior of which is hollow. The striking face of these woods isrelatively weakly inclined with respect to the vertical, which meansthat such clubs are dedicated to the taking of long shots.

[0004] More specifically, the head of a “wood” has an internal cavitydelimited by various walls. One of these walls forms the striking face.Among the walls adjacent the one forming the striking face are the wallforming the sole and the side walls and a crown wall. The rear of thecavity is closed off either by a rear wall, which may be of variousshapes, or by the prolongation of the various adjacent faces.

[0005] The invention is also of benefit to clubs known as “irons”. Thehead of an “iron” comprises a striking wall the front face of whichforms the actual striking surface and the rear face of which maypossibly be situated at the end of a cavity in the case of irons said tohave “peripheral weighting”.

[0006] As is known, and this is true of woods and irons, the strikingface is the face which makes impact with the ball. This impactpreferably occurs at the center of the striking face, also known as thesweet spot, so as to minimize the vibration transmitted up the shaft andso as to optimize the trajectory of the ball.

[0007] Given the forces exerted at the time of impact, the striking facehas a tendency to deform, and the lesser its thickness, the more it willdo so. This deformation toward the inside of the cavity of the headgenerates a trampolining effect which contributes to accelerating theball. It is known that the official regulations laid down by golfingfederations are seeking to limit this trampolining effect, so as toprevent performance from being excessively influenced by the mechanicalproperties of the hardware, for example by mounting the striking facewith a certain latitude for movement relative to the head, by insertingelastic elements, as described in document U.S. Pat. No. 5,505,453.

[0008] Various constructional steps have already been proposed in orderto make progress in this direction. Thus, a certain number of solutionsconsist in equipping the inside of the cavity with an element able toblock the deformation of the striking face, after a predetermineddeformation travel. Such solutions are described in particular indocuments U.S. Pat. No. 6,165,081, JP 81 502 30, JP 2001-238988, U.S.Pat. No. 6,299,547 and U.S. Pat. No. 5,499,814.

[0009] These solutions make it possible only to limit the deformation ofthe striking surface but have no influence on the trampolining effect.In addition, the disadvantages associated with these solutions lie inthe fact that the deformation of the striking face is altered abruptlywhen the back of the striking face comes into contact with the elementplaced for that purpose in the cavity. This discontinuity in thedeformation of the striking face may cause certain vibrations to arise.

[0010] It has also been proposed for the back of the striking face to beequipped with elements in the form of bridges forming springs, so as tomodify the intrinsic stiffness of the striking face. Such a solution isdescribed in particular in document JP-110 42 302. Such a constructionis relatively complicated because it combines the bending effect withthe warping effects of a leaf constrained at its ends. The deformationand therefore the elastic effect of such an embodiment are very random.

[0011] Other devices have also been proposed to influence thedeformation of the striking face. Thus, it is possible for the head tobe equipped with a free mass, which is kept in contact with the backface of the striking face by a resilient device. Upon impact with theball, this additional mass detaches from the striking face and movestoward the back of the head. This “beater” effect transfers some of theenergy of the impact to the additional mass. These devices have thedisadvantage of generating significant vibration and have no realinfluence on the trampolining effect, because the latter is determinedsolely by the inherent characteristics of the striking face, once theadditional mass detaches therefrom. Such devices are described forexample in documents U.S. Pat. No. 5,911,637, JP 05269224, JP 02-131788.

[0012] One of the objectives of the invention is to give the strikingplace an ability to deform which is relatively controlled in spite ofthe fact that the thickness of the striking face is relatively small.

[0013] Another objective of the invention is to give the club head astructure that allows the deformation of the striking face to beadjusted, while at the same time being easy to manufacture.

SUMMARY OF THE INVENTION

[0014] The invention therefore relates to a head of a golf club of the“wood” or “iron” type. In a known way, such a head has a wall whichforms the striking face, fixed to the rest of the head, and at least onewall adjacent the wall forming the striking face. Among these adjacentwalls are, in particular, the sole wall and the lateral and crown walls,and a rear wall in the case of woods.

[0015] According to the invention, the head is one which also comprisesan elastic leaf one end of which is fixed to one of the walls adjacentthe wall forming striking face, and the free other end of which bearswith preload against the back face of the wall of the striking face.

[0016] In other words, the head according to the invention includes aspring-forming leaf which is firmly fixed, for example by screwing orwelding, to the sole or alternatively the lateral walls or the crownwall in the case of a wood. The other end of this leaf exerts load onthe internal face of the wall of the striking face without being fixedto this wall. In that way, during the deformation movements of thestriking face, the end of the spring leaf remains in contact with theback of the striking face, and therefore produces a continuous andprogressive effect. The region of contact between the leaf and thestriking face can move slightly without generating excessive stresses inthe actual wall of the striking face. As the spring leaf is fixed onlyat one of its ends, its stiffness is practically constant regardless ofits deformation.

[0017] In addition, such a device, by limiting the vibrations of thestriking face, makes it possible to correct the sound resulting fromimpact of the ball on the club.

[0018] To improve the properties of this contact, it is possible to makeprovision for the free end of the elastic leaf to be curved, so thatcontact between the leaf and the striking face is tangential.

[0019] In practice, it will be preferable for the free end of theelastic leaf to bear in close proximity to the optimum point of impacton the striking face. To put it another way, the metal leaf exerts aforce behind the sweet spot.

[0020] For an iron with peripheral weighting which therefore has an opencavity, the constrained end of the leaf may be fixed to the bottom partforming the sole or to the upper or lateral flange contributing to theperipheral weighting. In the case of a wood, this end may be fixed toany one of the walls delimiting the closed cavity. The elastic leaf maybe made of metal or of glass composite or alternatively still of carbon.

[0021] The club head according to the invention may be produced usingvarious methods. Thus, a first method of manufacture may consist:

[0022] first of all, before fitting the plate that forms the wall of thestriking face on the head, in fixing one end of the metal leaf to a walladjacent the wall of the striking face,

[0023] then secondly, in fitting the wall of the striking face,elastically deforming the metal leaf,

[0024] then finally in fixing the plate that forms the wall of thestriking face to the head.

[0025] In other words, it is by fixing the plate that forms the wall ofthe striking face to the head that the metal leaf is placed undertension.

[0026] In an alternative form of embodiment designed specifically forwoods, the method may consist in:

[0027] first of all, in producing a hollow head comprising the crown,lateral, rear walls and the wall comprising the striking face,

[0028] then secondly, in fitting the sole to which one end of theelastic leaf has already been fixed, in such a way that the other end ofthe elastic leaf comes into contact with the wall of the striking face,experiencing a preload,

[0029] then finally in fixing the wall of the sole to the head.

[0030] In other words, in this alternative form, it is while the sole isbeing fitted that the elastic leaf is deformed to exert thecharacteristic force on the back of the striking face.

BRIEF DESCRIPTION OF THE FIGURES

[0031] The way of achieving the invention and the advantages that stemtherefrom will become clearly apparent from the description of theembodiments which follow, with support from the attached figures inwhich:

[0032]FIG. 1 is a brief perspective view of a head of a golf club of the“wood” type.

[0033]FIG. 2 is a view in section of the head of FIG. 1, on the roughlyvertical plane II-II′.

[0034]FIG. 3 is a view in section of the head of FIG. 1, on the roughlyhorizontal plane III-III′, mid-way up the head.

[0035]FIGS. 4 and 5 are sectional views similar to FIG. 2, showing theway in which the head according to the invention is mounted, accordingto two alternative forms of embodiment.

[0036]FIGS. 6 and 7 are vertical sections through the heads of two clubsof the “iron” type, produced according to two different embodiments.

EMBODIMENT OF THE INVENTION

[0037] As already mentioned, the invention relates to a golf club head(1). FIG. 1 depicts a head of the “wood” type. Such a head comprises astriking face (2), a sole (3), lateral faces (4, 5), a crown face (6)and a back wall (7) defined in the continuity of the lateral faces (4,5), of the crown face (6) and of the sole (3). The striking face isfixed rigidly to the rest of the head, for example by welding around itsperiphery. This head (1) also comprises a hosel (8) intended toaccommodate, inside a housing (9), the shaft of the club.

[0038] Traditionally, the striking face (2) has a horizontally scoredsurface. The point (10) situated on the striking face and correspondingto the optimum point of impact is generally known as the sweet spot.

[0039] In the form illustrated in FIG. 2, it can be seen that the sole(3) has a metal leaf (12) fixed by one of its ends (13), for example byscrewing. This screwing may be done as in the embodiment illustratedthrough the sole by at least one screw visible on the external face ofthe sole (3).

[0040] The screw-fastening system may also allow the tension with whichthe elastic leaf bears against the back (11) of the wall comprising thestriking face (2) to be adjusted via a slot made in the sole (3) (notdepicted).

[0041] Nonetheless, this end (13) of the leaf (12) may be fixed on theinternal face of the sole (3) by other means, particularly by welding orby bonding. This elastic leaf (13) is made of a relatively elasticmaterial, typically spring steel, or of an aluminum alloy of the Zicral®type, or alternatively of Kevlar®, carbon or glass composite.

[0042] This leaf (12) has another end (14) which is free and comes intocontact with the interior face of the wall forming the striking face(2). In the form illustrated, the end (14) of the leaf (12) is curved sothat contact between the leaf (12) and the back surface (11) of the wallof the striking face (2) is tangential with respect to the curvature ofthe end (14) of the leaf. Such a construction allows the end (14) toslide slightly with respect to the wall (11) of the striking face (2).

[0043] It can be seen that the region (15) of contact between the end(14) of the leaf (12) and the wall of the striking face (2) is situatednear the sweet spot (10), that is to say behind the ideal point ofimpact of the ball.

[0044] As illustrated in FIG. 3, the elastic leaf (12) may have acertain width that may vary according to the influence that thestiffness of the leaf is to have on the performance of the head. In anembodiment which has not been depicted, the leaf may have several pointsof contact.

[0045] Thus, in alternative forms, not depicted, the leaf may be widerthan is illustrated in FIG. 3. The region (15) of contact between theleaf (12) and the wall (11) of the striking face (2) may also be curvedin both directions, so that contact takes place over a region that isnarrower than the overall width of the leaf. In general, the stiffnessand deformation properties of the leaf can be tailored by usinggeometries and structures designed according to the need.

[0046] As regards its stiffness properties more specifically, it isimportant that the leaf (12) exert a permanent force on the wall of thestriking face (2), even when the striking face is unstressed. Putanother way, the leaf (12) is preloaded and exerts force.

[0047]FIG. 4 illustrates a method of manufacturing a head according tothe invention. Thus, the leaf (22) may first of all be fixed to theplate (23) that is intended to form the sole. Once the plate comprisingthe striking face (2) has been fitted to the rest of the head (1), theplate (23) is fitted, deforming the leaf (22), and this generates thepreloading force characteristic of the invention. The plate (23) is thensecured, for example by welding, to the rest of the head (1).

[0048] In another alternative form of embodiment, the leaf (32) is firstof all screwed or more generally fixed to the plate (23) forming thesole. This securing may take place either after the plate (23) has beenfixed to the head or alternatively beforehand, in the same way asillustrated in FIG. 5. When the sole is not formed from a separateplate, but forms an integral part of the rest of the head (1), the leaf(22) is then fixed by screwing or welding to the internal wall formingthe sole (23).

[0049] As illustrated in FIG. 5, before the striking face (2) is fitted,the leaf (32) is in its state of rest, without preload. As the strikingface (2) is fitted, the leaf (32) is deformed and pushed back into thecavity. The striking face (2) is then welded or more generally fixed tothe rest of the head in such a way that the leaf (32) exerts thecharacteristic preloading force.

[0050]FIGS. 6 and 7 illustrate the use of the invention on clubs of the“iron” type. More specifically, the club head (40) illustrated in FIG. 6has a wall (43) bearing the striking face (42) situated forward. Thishead (40) also comprises a rear cavity (48) the end of which consists ofthe back face (41) of the wall (43). The end (41) of the cavity (48) isdelimited peripherally by, at the bottom, the sole (44) and a peripheralband the top part (45) of which is illustrated in FIG. 6. According tothe invention, the leaf (49) may be fixed by one of its ends (46) to theupper face of the sole (44), the other end (47) of the leaf (49) bearswith preload against the back face (41) of the wall (43).

[0051] The arrangement of the leaf (49) can be altered as illustrated inFIG. 7 in which it can be seen that the leaf (59) is fixed by its end(56) to the top part (45) of the peripheral band.

[0052] It will be noted that the golf club head according to theinvention has the advantage that the characteristic leaf exerts apermanent force on the striking face which influences the deformation ofthis striking face as soon as it impacts with the ball. This influenceis continuous and can be adjusted through the choice of the leafgeometry.

1. A head of a golf club of the “wood” or “iron” type, having a wallforming the striking face fixed to the rest of the head, at least onewall adjacent the wall forming the striking face, namely in particularthe wall of the sole, and which also comprises an elastic leaf one endof which is fixed to one of the walls adjacent the wall forming thestriking face, and the free other end presses the preload against theback face of the wall of the striking face.
 2. The golf club head asclaimed in claim 1, wherein the elastic leaf if based on metal, oncarbon or on glass composite.
 3. The golf club head as claimed in claim1, wherein the elastic leaf is screwed, welded or bonded to the walladjacent the wall forming the striking face.
 4. The golf club head asclaimed in claim 1, wherein the free end of the elastic leaf is curved.5. The golf club head as claimed in claim 1, wherein the free end of theelastic leaf bears at, or in close proximity to, the sweet spot on thestriking face.
 6. The golf club head as claimed in claim 1, wherein theelastic leaf is fixed to the wall of the sole.
 7. The golf club head asclaimed in claim 1, and which is of the “wood” type.
 8. The golf clubhead as claimed in claim 1, and which is of the “iron” type.
 9. The golfclub head as claimed in claim 1, and which comprises means for adjustingthe force with which the leaf bears against the back face of the wall ofthe striking face.
 10. A method of manufacturing a golf club head asclaimed in one of claims 1 to 9, and which consists: first of all,before fitting the plate that forms the wall of the striking face on thehead, in fixing one end of the metal leaf to a wall adjacent the wall ofthe striking face, then secondly, in fitting the wall of the strikingface, elastically deforming the metal leaf, then in fixing the platethat forms the wall of the striking face to the head.
 11. The method ofmanufacturing a golf club head as claimed in one of claims 1 to 9, andwhich consists: first of all, in producing a hollow head comprising thecrown, lateral, rear walls and the wall comprising the striking face,then secondly, in fitting the sole to which one end of the elastic leafhas already been fixed, on its interior wall, in such a way that theother end of the elastic leaf comes into contact with the wall of thestriking face, experiencing a preload, then finally in fixing the wallof the sole to the head.